highly significantp < 0.01
3.2 Response surface analysis and model fitting Through quadratic linear regression fitting, the regression equation of the yield of pea starch extracted by ultrasonic-assisted alkali treatment was obtained as follows: Y = 53.50 + 0.90 X 1 + 1.61 X 2 + 0.84 X 3 + 0.29 X 1 X 2 - 0.66 X 1 X 3 + 0.61 X 2 X 3 - 2.55 X 1 2 - 4.42 X 2 2 - 2.03 X 3 2 The model difference was highly significant ( p < 0.01), as presented in Table 1 , and the lack of fit item difference was not significant ( p > 0.05).